While not everyone may realize it, the skin is classified as an organ of the human body, since it is a collection of specialized cells that perform a specific function. The average human has about 22 square feet of skin, and weighs about eight pounds. In addition to being the largest organ, this outer layer is also one of the most important. Skin is tasked with the vital job of providing a tough yet flexible line of protection, helping to keep us safe and healthy.
If you’ve never thought much about the skin, how it’s constructed or how it works, continue reading to learn about its anatomy as well as some of the other functions of the human skin.
The layers of the skin
The skin is made up of three different layers. Each of these layers is several layers of cells thick, and each one performs a specific function.
The epidermis is the visible, outermost layer of the skin. It is a waterproof layer of cells that keeps everything else inside it protected from bacteria, viruses and any other harmful substances that might be lurking in the environment. In addition, the epidermis contains melanocytes, which produce melanin, which determines skin color.
The epidermis itself is made up of four layers. The innermost layer of the epidermis is called the stratum germinativum. Here, new epidermal cells are created and slowly move outward to the outermost layer, the stratum corneum, as they age and mature. Once they reach the corneum they are eventually lost through natural shedding, or by more forceful means, such as friction caused by rubbing on objects.
The thickness of the epidermis varies depending on the part of the body. Some parts, like our hands, need more protection and therefore have a thicker layer than other parts. Regardless of where it is or how thick it is, the function of the epidermis is to protect the body from infection and damage.
The middle layer of skin is known as the dermis. Not only is this the thickest layer of skin, but it is also arguably the most important, as it has several key functions and components.
One of the most notable and important features of the dermis is its very construction. The dermis contains a thick, interwoven network of collagen fibers. These fibers help to give our skin both the toughness it needs to stay intact as well as the flexibility needed to be able to move, bend and stretch at will. The dermis also contains other types of cells, including blood vessels and fibroblasts, that serve many functions, including helping blood flow and regulating the moisture levels of the skin. Sweat glands and hair follicles can be found in the dermis.
All of these functions work together to help make skin a living, vibrant part of the human body, and the dermis is a crucial part of it.
The final layer of skin is the hypodermis. This innermost layer of skin serves two separate, but important, purposes.
First, the body stores fat in the hypodermis through the use of a special type of tissue known as adipose tissue, which contains adipocytes. These fat-storing cells store the fat in a convenient, easy-to-find spot until the body needs it later.
Of course, it’s this action which many people do not like, as an over-accumulation of fat cells can lead to people being overweight or even obese. While this process was evolutionarily necessary at one time to help people make it through lean times when food was scarce, these days this fat storage is more of a health concern than anything else.
The other important function of the hypodermis is to connect the skin to the rest of the body. This connection happens through loose connective tissue which allows the skin to stay connected to the various organs and other parts of the body directly underneath.
The role of pigmentation
The epidermis is responsible for skin pigmentation. Although it’s true that pigmentation plays a role in skin color, there are also other types of pigmentation that can occur here.
The epidermis contains a type of skin cell known as a melanocyte. The one job these specialty cells have is to produce melanin. “Melanin” is the scientific term for the pigment that determines skin color. The more melanin that is produced in the skin, the darker a person’s skin color is.
Melanin does more than just determine skin color, however. Melanin is also a natural sunblock that protects the skin and the rest of the body from harmful UV rays that are radiated from the sun. More melanin equals more UV protection, although being exposed to the sun helps to produce more melanin as well, which is where suntans come in to play, as darker-skinned people are less likely to tan or burn.
Unfortunately, as with any bodily system or function, skin pigmentation can go awry, causing one or more disorders that can be anything from mildly noticeable to extremely dangerous. These disorders can include hypo-pigmentation, which is a lightening of the skin in an area; hyperpigmentation, which is a darkening of the skin; albinism, which is a total lack of pigmentation; and melasma, which is a dark spot that appears in a specific area of the skin.
Other structures of the skin
In addition to having the various layers and functions we’ve already talked about, no basic discussion of the skin is complete without talking about these other, important structures:
Hair follicles reside in the dermal layer of the skin. However, while that is where they begin, the hair they produce also comes through the epidermis. Hair production is an extremely complex process. A combination of hormones and other chemicals help to produce many types of hair that can be found on different parts of the body during different phases of life.
While there are many disorders that can be associated with hair growth, the most common is hair loss.
The sensory nerve endings of the skin are located in the epidermis, and it is these structures that help supply the skin with nerves. Because of these nerve endings, we are able to feel sensations such as temperature, texture and pain.
In addition to helping a person feel and interact with the outside world, dermatologists can use sensory nerves during a skin biopsy to aid in diagnosing various conditions and disorders.
Sweat glands, or “sudoriferous glands” are essential for life. Without them, a person would soon overheat, which could lead eventually to death. The sweat glands are located in both the dermis and hypodermis and are globular structures surrounded by adipose tissue. There are several types of sweat glands, depending on their location. The human body has many sweat glands in total. An average palm, for example, contains over 350 sweat glands per cubic centimeter. Other parts of the body contain different amounts. Each and every one of us has tens of thousands of sweat glands all over our bodies, helping to keep us cool!
Dermatology in Columbia, Irmo, Camden and Lexington
The skin is a much more amazing organ than originally thought, full of layers – both literal and metaphorical. From keeping our body protected to helping us keep our cool to aiding in our understanding of the outside world, our skin is a complex work of art. So, it is an organ that needs to be protected and cared for, and any problems, conditions or disorders should be treated right away. Take care of your skin, and it will take care of you!
If you have a skin issue that you need to address, contact us today.